Although a fair amount of time is devoted to Bannon's biography -- including his segue from Wall Street to Hollywood, which made him wealthy without quenching his political appetites -- the meat of this Michael Kirk-directed hour focuses on Bannon's time at Breitbart and his views regarding an inevitable conflict between the West and Islam.

Bannon "wanted to fundamentally change Washington," as the narration explains, and at first saw former Alaska governor Sarah Palin as his populist conduit. Disappointed when she chose not to run in 2012, he turned his attention elsewhere, and found a kindred spirit and "vehicle for his perspectives" in Donald Trump -- less in policy than the way they approached politics.

"It's more about destroying enemies," says former Breitbart staffer Ben Shapiro. "I think that's where he and Trump meet."

Bannon, for example, is credited with orchestrating the campaign's counter-attack to the "Access Hollywood" tape in which Trump talked about grabbing women, trotting out Bill Clinton's former accusers at a press event designed to deflect the media's focus.

The main question, after Trump publicly downplayed Bannon's role in the administration, is the extent of his current influence and whether he can survive the relentless tumult. Journalist Jane Mayer describes the strategist, not very reassuringly, as being mindful of the forces arrayed against him and on "a kamikaze mission" to get as much done as quickly as possible.

Given how Bannon has clung to the shadows, Kirk fleshes out the film with his subject's rare interviews and clips from documentaries that he directed or championed, highlighting his apocalyptic vision of the future. "Generation Zero," for example, released in 2010, predicted a coming world war. (Some of those statements are particularly notable juxtaposed with images of the strategist with President Trump on his current trip abroad.)

As noted, "Bannon's War" is a snapshot of a battle that remains a fast-moving work in progress. Yet Frontline has once again provided the sort of sober reporting and context that at least helps viewers come away with a clearer sense of who the combatants are, and in Bannon's case, what animates him.

"Bannon's War" will air May 23 at 10 p.m. on PBS.

CNNMoney (Los Angeles) First published May 23, 2017: 9:58 AM ET

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